1. Field of the Invention
The present invention generally relates to light source modules and particularly, to a light source module of light emitting diodes which generates white lights.
2. Description of Related Art
Light emitting diodes (LEDs) have excellent characteristics, for example, small volume, good optical properties, low energy consumption, and long lifespan, which make them very suitable for use in illumination devices. With the improvement of light emitting efficiency, LEDs are widely employed as light source for illumination.
A typical light source module uses a blue LED as an initial light source to produce a white light. The blue light emitted from the blue LED strikes fluorescence material within the light source module to generate a yellow secondary color light. The combination of the yellow and residual blue lights produces a white light. However, if a proportion of the residual blue light to the yellow light in one lumen of the white light increases, the white lights have a blue color bias. Conversely, if the proportion decreases, the white lights have a yellow color bias.
A light source module generally includes an array of LEDs that form a small area of a light source. Initial lights emitted from each of the LEDs are diffused. The intensity of the initial lights emitted from a LED gradually reduces from the center to the periphery of the LED. Thus, the intensity of the initial lights emitted from the small area of light source gradually reduces from the center to the periphery of the module. White lights emitted from the module bias the color of the initial lights near the center of the module, and bias the color of the lights fluoresced from fluorescence materials near the periphery of the module. As a result, the color of the white lights is not evenly distributed.
Therefore, a new light source module is desired in order to overcome the above-described shortcoming.